


What Lurks Beneath the Surface

by trajektoria



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Angst, Fluff, Horror, Lovecraftian, M/M, OctoJohn, Terror, a bit - Freeform
Language: English
Status: Completed
Published: 2013-10-30
Updated: 2013-10-30
Packaged: 2017-12-30 21:27:07
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 3,133
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1023570
Author URL: https://archiveofourown.org/users/trajektoria/pseuds/trajektoria
Summary: <blockquote class="userstuff">
              <p>In his never-ending pursuit of knowledge, Sherlock acquires a strange octopus. John doesn't approve, sensing that something is wrong. The gut feeling rarely fails him. Unfortunately.</p>
            </blockquote>





	What Lurks Beneath the Surface

**Author's Note:**

> Big thanks to [captainjennhart](http://captainjennhart.tumblr.com/) who helped me improve the text.

“You've really gone too far this time, Sherlock. What the hell is that?!” John barked, putting his hands on his hips, annoyance rolling off him in waves. Unbelievable. He couldn't even leave the detective alone for three days without him doing something utterly stupid and/or damaging to their flat. This time the disaster took form of an algae-covered fish tank standing innocently in the middle of the table in the living room. Well, had the tank been empty, John would have been mostly okay with that, save perhaps for the smell. But alas – no. Sherlock was obviously mad enough to put a living organism there, and one that definitely shouldn't be kept in the middle of London.

John leaned a little closer, staring at the... thing inside. He wasn't a veterinarian but he possessed some rudimentary knowledge about sea creatures, mainly thanks to being unemployed for a long time and watching lots of Animal Planet back in the day. The doctor was fairly sure he had never seen anything like it. It resembled a little octopus: about six inches tall, blue tentacles and whatnot, but where cephalopods usually had their heads, this specimen had a black, gooey, fluctuating structure with a pair of yellow eyes right in the middle. Without any rational reason, apart from a gut feeling that was impossible to ignore, John experienced an instant and severe revulsion aimed at the jelly abomination. Really, Sherlock was like a child sometimes; he shouldn't be left alone without adult supervision for long. Where did he even find that thing? 

“I expected that your greetings would be slightly warmer after a few days of separation. How was the conference in Dublin? Awfully dull, I suppose,” Sherlock stated flippantly, emerging from the kitchen. As far as John could tell, the detective was naked under his burgundy dressing gown – the belt wasn't even properly knotted. Most probably Sherlock had done it on purpose to evoke a certain response from his lover. John's cheeks flushed, but the sight didn't avert his thoughts from more pressing matters. Namely, the animal crisis at 221b Baker Street.

Still, when those heart-shaped lips rested on his and he felt Sherlock's hand on his neck, John couldn't refuse to reciprocate the affection. Damn, he did miss his insane detective during those days of absence. It was impossible to deny. 

“Really, though, Sherlock. What the hell's that? I don't want you harbouring a mutated squid in our apartment!” he protested adamantly as soon as his partner pulled back.

“It's not a squid, it's an octopus,” Sherlock huffed, as if that was the most obvious thing in the world. “Besides, it's a fascinating specimen to study. Did you know that its ink has paralytic qualities? I've run a few tests and---”

John shook his head, too impatient and peeved to listen to the detective's excited babble. 

“Where did you get it? I doubt you can actually fish out cephalopods from the Thames. Well, unless Chinese joints are dumping leftovers into the river again,” he quipped with sarcasm. 

“This particular specimen has been found near Bermuda, the area known by lesser minds as the Bermuda Triangle. The species hadn't been identified yet, which obviously indicates that it is an extremely rare animal.”

John scoffed. Since when was Sherlock even interested in the animal world? He asked that question aloud.

“Oh, John. I'm interested in mysteries! Secrets of any kind that can stimulate my intellect! My brain rebels at stagnation!” Sherlock had always had a flair for being dramatic. “And this octopus's very existence baffles me greatly. What's the purpose of its unstable body?” 

“All right, Darwin, but how did you even get it? I don't suppose you went scuba diving to Bermuda while I was away?”

For the first time Sherlock seemed a little uncomfortable and maybe even a tad guilty. 

“Well, no, I didn't. I've... acquired it differently.”

John was full of misgivings. 

“Yes... And how exactly did you _acquire_ it, hm?”

The man was reluctant to answer, but John knew how to handle him. After a few minutes of coaxing and grilling, the detective finally spilled the beans.

“I've borrowed it from a secret research facility in Dover. Well, not so secret apparently, and their defence system was just laughable.”

“Borrowed. Research facility. Great, just great,” John sighed tiredly, pinching the bridge of his nose in exasperation. He had a hard time not hitting the ceiling. “Sherlock, tomorrow you're gonna give him back or so help me.”

“But---”

“No buts, Sherlock. You need to get rid of it.”

The detective pouted like a petulant child. 

“John, despite its unflattering appearance, it's a very amiable creature and, frankly speaking, I don't understand your negative attitude towards it. Give it a chance,” he persuaded, and before John could scream in terror or voice his protest in a more dignified manner, the detective plunged his hand into the fish tank.

“Sherlock!” John gasped, watching in astonishment as his lover grasped the creature carefully and placed it on his flat palm. With the index finger of his other hand, Sherlock gently petted the octopus's shapeless head. Oddly enough, the creature seemed to enjoy the caress, since he responded by stroking Sherlock's thumb with its tentacle. 

“You see? It's not so bad,” Sherlock smiled smugly, pushing his hand with the creature encouragingly nearer John.

“Oh, no. I won't touch it. No way.” He crinkled his face in utter disgust.

“John...”

“No.”

“You've touched worse things during your career,” Sherlock observed, clearly bent on making John take a liking to their new pet. That was probably his plan – to make the strange octopus their pet, so he could study it to his heart’s delight. 

John sighed in annoyance. He knew that he could resist until his face turned blue, but the quickest way to get this over with was to obey Sherlock's request. 

“Fine. But you still have to give him back,” John said adamantly, and, against his better judgement, extended his hand to touch the ugly critter. Maybe it was only his imagination, but he could have sworn that the creature glowered at him and the temperature in the room dropped a few degrees. John instinctively wanted to pull back; it was too late, though. The weird octopus proved that beside tentacles it also had teeth. The mouth appeared suddenly on the head and a few fangs sunk into John's skin, drawing blood.

“Ouch! Bloody hell!” John yelped in pain, yanking his hand free. “It bit me!”

At least Sherlock took it seriously. Turning pale, he quickly put the creature back in the fish tank. 

“John, are you all right?” he asked, tones of panic in his voice as he leaned down to take a look at John's throbbing finger.

“I'm fine. But this monster has to disappear!” he said through his teeth, his face contorted in fury. He stormed to the bathroom to clean the wound and stick a band-aid on it. 

After a moment of hesitation, Sherlock went after him. He stood in the doorway, looking guilty. 

“I'm sorry, John. That never happened before, the octopus never behaved aggressively,” he said, thinking about the reason behind the sudden attack. “Did you provoke it in any way?”

“No, of course not!” John hissed, pouring some peroxide over the biting mark. Should he go to the hospital? He studied the wound carefully, but it didn't show any signs of infection or a poison. It didn't even hurt much. He felt fine, considering. A band-aid should do. He was lucky. “Still, you need to get rid of it in the morning.”

Sherlock didn't look too happy about it, but he sighed in defeat.

“All right, I will,” he promised, taking a few steps closer to John with unaffected grace. His long arms closed around the doctor's waist and he moved his lips to John's ear, breathing hot air on it. “But let's forget about it for now. Let me greet you properly... and preferably several times.”

John giggled despite himself and turned around to give Sherlock a heated kiss. 

The water in the fish tank gurgled angrily and for a second turned a deep shade of sickly red. 

* * *

“John!” A shout full of awe and elation came from the living room. John mumbled something incoherently and rolled to his other side. It was far too early to leave the bed. Sherlock kept him awake for most of the night - not that John complained - so he could use some rest. 

“John! You have to see this!” The voice was implacable. John sighed. No more sleeping today. He cursed under his breath, but lifted the covers and stood up with difficulty, stifling a yawn. 

“John! Come quickly!”

“Coming, coming...” he mumbled and reached for his briefs, carelessly tossed on the floor the night before. He put them on and staggered groggily out of the room. “What's going on?”

Sherlock didn't bother to get dressed. He stood naked before the fish tank with the most baffled and intrigued expression that John had ever seen.

“Look, John,” he said, stepping out a bit to give some room to his lover.

“You were supposed to throw it aw---” John began in an irritated tone, but the words died in his throat when his eyes focused on the creature.

It... changed. It still had blue tentacles, but above them... well... John couldn't believe his eyes. He saw himself. Or at least a miniature version of himself from the waist up. The octopus had the head, arms, and torso of Sherlock's flatmate. It had tiny human fingers, blue irises, a nose, and ears. Hell, it even had John's sandy hair and the bullet scar on its shoulder. A tiny copy of Dr. Watson but with a set of bluish appendages instead of legs. John was dumbfounded. 

“What the hell...?” John gasped, his voice full of terror as he looked at his lover, awaiting explanation. Sherlock was far from being petrified. He was full of energy. His face, lit up like a Christmas tree, was radiating excitement and delight to have such a mystery before his very eyes.

“Your blood, John. He must have absorbed your DNA and changed himself to resemble you. Why did he do it? And why did he leave tentacles? He couldn't change them? He's still too weak to perform such a change? Or perhaps there's another reason?” Sherlock wondered aloud. John didn't share his scientific passion. His expression was sour. He was horrified.

“Oh, so now you're calling it 'he'?” he asked reproachfully. Sherlock didn't take a hint.

“Yes. He has developed anthropomorphic features, so this change of attitude is validated. I've decided to call him 'OctoJohn', it has nice ring to it, hasn't it?” He smiled. John was not amused.

“OctoJohn? For God's sake, Sherlock!” he shouted in aggravation, staring at the miniature cephalopody version of himself. The little creature seemed impassive, but there was something unsettling about him. Just staring at him, John felt his skin crawl. “Sherlock, he's creeping me out. I don't care if he's an eighth wonder of the world. I don't want him in our flat.”

Sherlock turned on his heel and looked at John in disbelief.

“John, you can't be serious! I've never seen a more fascinating animal in my life!”

“Well, good for you. But I mean it. The octopus has to go.”

Sherlock begged him to change his mind, but John didn't want to hear about it. A bad feeling was growing in the pit of his stomach and he knew the octopus was nothing but trouble. 

“John, please. A week. That's all I'm asking you. A week to finish my research and then I will return him. I promise,” he said desperately. Vows were Sherlock's last resort to get what he wanted, John was aware of that. For a long moment he just stared at his lover, creasing his forehead, but finally yielded. 

John nodded, knowing he would regret it.

“All right. A week. But not even an hour longer, you hear me?”

Sherlock beamed at him happily. He put his hands on John's cheek and pressed his lips to John's with a loud smack.

Without saying another word, Sherlock ran to the kitchen and put a sturdy apron over his naked body, simultaneously slipping with gaiety into his mad scientist mode. He was beyond John's control now. 

* * *

The days kept passing slowly. The detective barely ate, slept, or talked, completely absorbed in his research. He and the creature seemed to get along quite well. The same couldn't be said about the octopus and John, though. It was irrational, but he was sure that this _OctoJohn_ hated him with every fibre of his body. John constantly felt his burning gaze on himself. Not only that, but each time John came closer to Sherlock, the little octopus was glaring daggers at him. Was he jealous? What an odd thought! That couldn't possible be true. It was just a mindless animal!

John observed with growing uneasiness how the creature kept getting bigger and bigger. By the second day he couldn't fit into the palm of Sherlock's hand anymore. By the end of the fourth day, he was as big as the detective's forearm. The fish tank got too small for him and his tentacles stuck out of it, moving languidly in the air. John hated to even look at him, overwhelmed with disgust. He didn't say anything, though, honouring the deal. A week and they would say goodbye to this abnormality forever. John could hardly wait. 

When on the evening of the fifth day the octopus spoke, John couldn't stand it any longer. He was in the kitchen, fixing himself a sandwich when he heard his own voice resounding through the flat. At first he thought Sherlock was watching some kind of a movie of them together he’d recorded with his phone. That seemed like a plausible explanation, considering all the mad things Sherlock was capable of doing. But then the voice began talking about the depths of the ocean, about a sunken city, about different dimensions. John peeked out from the kitchen. Sherlock was... talking with the octopus and... it responded in a perfect John's voice. How was that even possible, it didn't have vocal chords!

That was the straw that broke the camel's back. John couldn't tolerate it any longer. Was Sherlock blind? Couldn't he see with what dark, dangerous forces he was meddling with? He shouldn't have got this monster in the first place!

“Sherlock, I don't care about our deal. He's dangerous! He talks like me, what will come next? I don't want to feel threatened in my own house. The octopus must go. Now!” he demanded forcefully.

“Oh, John, don't be so dramatic,” Sherlock said nonchalantly, turning around. “Can't you see how unique this creature is? A sentient being capable of imitating other organisms, living at the bottom of the ocean! I need to know everything there is!”

“Sherlock, I really don't care. I've been lenient; I allowed you almost everything. Head in a fridge? Fine. A corpse in the shower? All right. Bacteria in the ham? No problem. But now I'm putting my foot down. Get rid of him.”

“But John---”

“Him or me. The decision is yours, Sherlock.”

The detective's eyes widened. It wasn't an empty threat. John really meant that. He was ready to leave him, ready to move out of Baker Street. 

No, John... He couldn't end up alone again. John was everything to him. 

“I'll take care of it in the morning,” he said in defeat, hunching his back. 

John let out a relieved sigh, thankful that his lover had finally seen some sense.

“Thank you, Sherlock. I really appreciate that.” John took a step closer and put his hand on the man's shoulder, letting the pads of his fingers brush against the soft skin on the Sherlock's neck. “Let me show you just how much I appreciate that...” he muttered, giving Sherlock the most lustful of glances. 

“Mhm... I won't say 'no' to that...” Sherlock replied with a winsome grin, tilting his head down to join their lips together. No experiment was worth losing John.

The water in the fish tank rippled and the tentacles lashed around angrily.

* * *

When John woke up later that night, it was already too late. He parted his eyes slightly, feeling a strange, moist weight on his shoulder. The sight of OctoJohn spluttering ink right into his face was the last image his dazed mind registered before his body went numb. He couldn't lift a finger. Paralytic qualities – the words Sherlock spoke before echoed in his brain. 

“You shouldn't have interfered. You shouldn't have returned. He doesn't need you anymore. He has me. I'm better than a puny human...” the octopus said mockingly. A tip of his tentacle smeared across Sherlock's cheek, leaving a blotch of ink on his pale skin. “Just enough to keep him dreaming for a few hours. We don't want to be disturbed. I want to savour this moment. Literally,” he hissed an explanation and slowly lifted the covers from John, moving down his body. 

The doctor wanted to scream, wanted to fight, wanted to tear the squid to shreds. He couldn't do anything. He was helpless like a baby, unable to defend himself or warn Sherlock. The doom was coming and he couldn't do anything to stop it. 

OctoJohn started with a bite on John's ankle. Very carefully, not to make a mess, he drained the blood from the doctor's body. As the man's consciousness began to fade, he thought only about Sherlock, who was unaware of the fate laid before him. Poor, poor Sherlock...

When the octopus bit on John's flesh, tearing a chunk off, he was already dead, just a lifeless shell. OctoJohn began to change, morph. With each bite his form kept shifting as he assimilated more and more DNA, rising in power. Gnawing the meat, crushing the bones, swallowing tendons – he clicked his tongue in pleasure at such a feast. 

An hour later OctoJohn lifted his gaze and looked into the large mirror. No, he wasn't 'octo' anymore. The reflection of a grown man with blue eyes and short blond hair smiled at him menacingly. He glanced at the new pair of legs he managed to grow. Yes, his transformation was full now. A proper human being, but at the same time so much more. So much more...

He smiled to himself as he laid down on the empty spot not long ago occupied by that annoying doctor. His time had passed. Now someone else would take his place beside this curious researcher. The new John draped his arm over Sherlock's waist and snuggled against his warm back, closing his eyes. No one would ever suspect a thing.

**Author's Note:**

> I'm really sorry. I love OctoJohn and I think he's the cutest critter ever, but I had to write this fic as a horror to meet the requirements of this challenge. Don't hit me too hard.


End file.
